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POST UTME LASU 2020 Physics | Objective

Are you preparing for POST UTME LASU exams? Reviewing past questions is one of the most effective ways to guarantee a high score. This practice hub features authentic 2020 Physics (Objective) questions designed to simulate the real exam environment.

Practice these randomly selected questions to test your readiness.

Question 1

A light ray is incident on a spherical mirror with a radius of curvature of 20 cm. If the angle of incidence is 30°, calculate the angle of reflection.

A. 15°

Correct B. 30°

C. 45°

D. 60°

Correct Answer: B

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Question 2

A 100 W bulb is connected to a 220 V mains supply. Calculate the current drawn by the bulb.

A. 0.45 A

Correct B. 0.5 A

C. 0.55 A

D. 0.6 A

Correct Answer: B

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Question 3

A radioactive subs\tance has a half-life of 5 years. If the initial activity is 100 Bq, calculate the activity after 10 years.

Correct A. 12.5 Bq

B. 25 Bq

C. 50 Bq

D. 100 Bq

Correct Answer: A

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Question 4

A sound wave has a frequency of 200 Hz and a wavelength of 1.5 m. Calculate the speed of the sound wave.

A. 300 m/s

B. 400 m/s

Correct C. 500 m/s

D. 600 m/s

Correct Answer: C

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Question 5

A heat engine operates between a source temperature of 500 K and a \sink temperature of 300 K. If the efficiency of the engine is 30%, calculate the work done by the engine.

A. 1000 J

B. 2000 J

Correct C. 3000 J

D. 4000 J

Correct Answer: C

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Question 6

A 2 kg block of ice at 0°C is placed in a 5°C water bath. Assuming the specific heat capacity of ice is 2090 J/(kg°C) and the latent heat of fusion of ice is 334,000 J/kg, calculate the heat energy required to melt the ice completely.

Correct A. 2.15 x 10^5 J

B. 2.15 x 10^4 J

C. 2.15 x 10^3 J

D. 2.15 x 10^2 J

Correct Answer: A

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Question 7

A 50 Hz AC voltage source has a peak voltage of 100 V. If the current is 5 A, calculate the power factor of the circuit.

Correct A. 0.5

B. 0.7

C. 0.9

D. 0.95

Correct Answer: A

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Question 8

A magnetic field of 0.5 T is applied to a coil of 100 turns with a radius of 0.05 m. If the current is 2 A, calculate the torque experienced by the coil.

Correct A. 0.1 Nm

B. 0.2 Nm

C. 0.3 Nm

D. 0.4 Nm

Correct Answer: A

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Question 9

A particle is projected at an angle of 60° to the horizontal with an initial velocity of 20 m/s. If the acceleration due to gravity is 9.8 m/s², calculate the time taken for the particle to reach its maximum height.

A. 1.5 s

Correct B. 2.0 s

C. 2.5 s

D. 3.0 s

Correct Answer: B

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Question 10

A simple harmonic motion has a frequency of 5 Hz and an amplitude of 0.1 m. If the initial phase angle is 30°, calculate the displacement of the particle at t = 0.1 s.

A. 0.05 m

Correct B. 0.06 m

C. 0.07 m

D. 0.08 m

Correct Answer: B

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Question 11

A particle of mass 2 kg moves in a circular path of radius 3 m with a cons\tant speed of 4 m/s. If the particle is subjected to a centripetal acceleration of 2 m/s^2, what is the magnitude of the net force acting on the particle?

A. 8 N

B. 10 N

Correct C. 12 N

D. 16 N

Correct Answer: C

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Question 12

A projectile is launched from the ground with an initial velocity of 20 m/s at an angle of 60° above the horizontal. If air resis\tance is neglected, what is the maximum height reached by the projectile?

A. 10 m

Correct B. 15 m

C. 20 m

D. 25 m

Correct Answer: B

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Question 13

A 10 μF capacitor is connected in series with a 20 Ω resistor and a 5 V battery. If the switch is closed at time t = 0, what is the charge on the capacitor after 2 seconds?

A. 0.1 C

B. 0.2 C

Correct C. 0.3 C

D. 0.4 C

Correct Answer: C

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Question 14

A 5 kg block is attached to a horizontal, massless spring with a force cons\tant of 100 N/m. If the block is displaced by 2 m from its equilibrium position and released from rest, what is the maximum speed of the block?

A. 2 m/s

B. 4 m/s

Correct C. 6 m/s

D. 8 m/s

Correct Answer: C

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Question 15

A 10 μF capacitor is connected in parallel with a 20 μF capacitor. If a 5 V battery is connected across the combination, what is the equivalent capaci\tance?

A. 10 μF

Correct B. 15 μF

C. 20 μF

D. 25 μF

Correct Answer: B

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Question 16

A thermodynamic system undergoes a cyclic process, where the initial and final states are identical. If the system absorbs 500 J of heat energy during the process, and the work done by the system is 200 J, what is the change in internal energy of the system?

Correct A. -300 J

B. 300 J

C. -500 J

D. 500 J

Correct Answer: A

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Question 17

A magnetic field is produced by a current-carrying wire. If the current is 2 A and the length of the wire is 0.5 m, what is the magnetic field strength at a dis\tance of 0.2 m from the wire?

A. 0.1 T

Correct B. 0.2 T

C. 0.5 T

D. 1 T

Correct Answer: B

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Question 18

A gas is confined to a container with a volume of 0.5 m^3. If the temperature of the gas is increased from 300 K to 400 K, what is the new volume of the gas?

A. 0.5 m^3

B. 1 m^3

Correct C. 1.5 m^3

D. 2 m^3

Correct Answer: C

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Question 19

A circuit consists of a 100 Ω resistor, a 200 Ω resistor, and a 50 Ω resistor connected in series. If a voltage of 12 V is applied across the circuit, what is the current flowing through the 50 Ω resistor?

A. 0.2 A

B. 0.4 A

Correct C. 0.6 A

D. 0.8 A

Correct Answer: C

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Question 20

A thermodynamic system undergoes a process where the temperature remains cons\tant. If the system absorbs 200 J of heat energy, and the work done by the system is 100 J, what is the change in internal energy of the system?

A. -100 J

B. 0 J

Correct C. 100 J

D. 200 J

Correct Answer: C

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Question 21

A beam of light of wavelength 500 nm is incident on a glass plate of re\fractive index 1.5. If the angle of incidence is 30°, what is the angle of re\fraction?

Correct A. 20°

B. 30°

C. 40°

D. 50°

Correct Answer: A

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Question 22

A particle of mass 2 kg is moving in a circular path of radius 3 m with a cons\tant speed of 4 m/s. What is the magnitude of the centripetal acceleration?

A. 2 m/s²

B. 4 m/s²

Correct C. 6 m/s²

D. 8 m/s²

Correct Answer: C

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Question 23

A radioactive sample has a half-life of 5 years. If the initial activity is 100 Bq, what is the activity after 10 years?

A. 20 Bq

Correct B. 40 Bq

C. 60 Bq

D. 80 Bq

Correct Answer: B

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Question 24

A heat engine operates between two temperatures, 300 K and 400 K. If the efficiency of the engine is 30%, what is the temperature of the hot reservoir?

A. 350 K

B. 400 K

Correct C. 450 K

D. 500 K

Correct Answer: C

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Question 25

A magnetic field of strength 0.5 T is applied to a current-carrying wire of length 2 m. If the current is 2 A, what is the force experienced by the wire?

A. 0.1 N

Correct B. 0.2 N

C. 0.3 N

D. 0.4 N

Correct Answer: B

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